Organic working fluid turbine half-speed mechanical seal and working fluid recovery system

Abstract

The application discloses an organic working medium turbine semi-rotating speed mechanical seal and working medium recovery system, which comprises a rotating ring assembly, a gear shaft assembly, an intermediate ring assembly, a pushing ring assembly, a static ring assembly, a positioning fastening ring assembly and a working medium recovery system; the rotating ring assembly drives the intermediate ring assembly to rotate at half speed through the gear shaft assembly; a shaft sleeve dynamic ring on the rotating ring assembly and a soft ring on the intermediate ring assembly form a first sealing friction pair, and a hard ring on the intermediate ring assembly and a static ring on the pushing ring assembly form a second sealing friction pair; the relative rotating speed of the first sealing friction pair and the second sealing friction pair is half of the rotating speed of a main shaft; process nitrogen is introduced into an isolation gas chamber; the pressure of the nitrogen is higher than that of the organic working medium gas; and the working medium recovery system is communicated with a mixed gas outlet. The application can reduce the friction heat, avoid the overheating failure of a sealing surface, improve the reliability and service life of large-size high-speed mechanical seal work, and realize the external zero leakage of the organic working medium and the separation and recovery of the working medium.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of mechanical seal, and particularly relates to an organic working medium turbine semi-rotational speed mechanical seal and working medium recovery system. BACKGROUND

[0002] The turbine of double-working-medium geothermal power generation adopts isopentane, n-pentane, cyclopentane and other combustion-type organic working medium as the circulating medium. These media have the characteristics of flammability and explosiveness, and are absolutely not allowed to leak outward, so that the turbine shaft end seal is required to be extremely high. Since the mechanical seal is suitable for the working condition of dangerous, flammable and toxic medium, the seal of the organic working medium turbine widely adopts the mechanical seal.

[0003] The mechanical seal is tightly attached to the dynamic ring assembly (rotating ring assembly) and the static ring assembly to form a sealing surface. The dynamic ring assembly and the static ring assembly are a pair of high flatness friction pairs, and the gap between the two when rotating relative to each other is in the micron level, which can effectively prevent internal fluid from leaking from the sealing surface. During operation, a large amount of heat is generated between the dynamic ring assembly and the static ring assembly. The sealing surface of a large-size or high-speed mechanical seal is prone to deformation and failure due to overheating, so the sealing diameter of the mechanical seal is relatively small. For example, the API682 standard stipulates that the sealing surface diameter of the mechanical seal is less than 4.3 inches (110 mm), and the service life can reach 25,000 hours under such size limitation.

[0004] Large-diameter mechanical seals are mainly used in low-speed scenarios. For example, large-size mechanical seals are usually used in stirred tanks, but their working speed is usually only a few dozen revolutions per minute, and they cannot be used in high-speed scenarios. In order to meet the market demand for large-size mechanical seals in high-speed scenarios, current international well-known manufacturers customize and develop high-speed mechanical seals with a maximum of 12 inches, which are not only very expensive but also in a necked state, which is not conducive to engineering popularization and application.

[0005] The organic working medium turbine adopts a horizontal center surface, so the mechanical seal installation can only pass through along the rotor shaft extension, and the rotor shaft neck diameter needs to be smaller than the inner diameter of the mechanical seal shaft sleeve. Therefore, the size of the rotor shaft neck of the organic working medium turbine is relatively small. However, the critical speed and anti-vibration performance of the heavy rotor with a small-size shaft neck cannot meet the use requirements. The rotational speed of the organic working medium turbine for double-working-medium geothermal power generation and offshore platform gas turbine high-temperature flue gas waste heat power generation is 3000 rpm or 1500 rpm, and the single-machine power can reach 20 MW to 30 MW. In order to meet the safe and stable operation of the rotating parts of the organic working medium turbine,

[0006] Increasing the rotor shaft diameter and mechanical seal shaft diameter, and developing 12-inch to 20-inch high-speed mechanical seals for 20MW to 30MW-class organic working fluid turbines, is crucial for ensuring the safe and stable operation of the units. However, for domestic manufacturers, the development cycle for high-speed mechanical seal friction pairs is long and technically challenging. In summary, China faces two major technical challenges in this field: first, the development cycle for high-speed, large-size mechanical seal friction pairs is long and technically challenging, especially in terms of frictional heat generation control; second, absolute zero leakage and effective recovery of the organic working fluid must be achieved.

[0007] Against this backdrop, the present invention proposes a half-speed mechanical seal and working fluid recovery system for organic working fluid turbines. This mechanical seal can reduce the relative speed of the sealing friction pair, thereby reducing frictional heat generation, avoiding overheating failure of the sealing surface, improving the reliability and service life of large-size high-speed mechanical seals, and achieving zero leakage of organic working fluid to the outside and separation and recovery of the working fluid; ultimately achieving safe, stable and environmentally friendly operation of organic working fluid turbines. Summary of the Invention

[0008] The purpose of this invention is to address the shortcomings of existing technologies by providing a turbine half-speed mechanical seal and working fluid recovery system for organic working fluids. This mechanical seal can reduce the relative rotational speed of the sealing friction pair, thereby reducing frictional heat generation, avoiding overheating failure of the sealing surface, improving the reliability and service life of large-size high-speed mechanical seals, and achieving zero leakage of organic working fluids to the outside and separation and recovery of the working fluids.

[0009] The technical objective of this invention is achieved through the following technical solution:

[0010] An organic working fluid turbine half-speed mechanical seal and working fluid recovery system includes a rotating ring assembly, a gear shaft assembly, an intermediate ring assembly, a push ring assembly, a stationary ring assembly, a positioning and fastening ring assembly, and a working fluid recovery system. The rotating ring assembly drives the intermediate ring assembly to rotate at half speed via the gear shaft assembly. The rotating ring assembly's bushing rotating ring and the soft ring on the intermediate ring assembly form a first sealing friction pair, and the intermediate ring assembly's hard ring and the push ring assembly's stationary ring form a second sealing friction pair. The relative rotational speed of the first and second sealing friction pairs is half the main shaft speed. Process nitrogen is introduced into the isolation chamber to remove frictional heat. The nitrogen pressure is higher than the organic working fluid gas pressure to prevent the working fluid from leaking into the atmosphere. The working fluid recovery system is connected to the mixed gas outlet for separating and recovering the mixture of organic working fluid and nitrogen.

[0011] Preferably, the sealing bushing of the rotating ring assembly is fixed to the main shaft by a positioning and fastening ring assembly and rotates together with it; the sealing bushing is provided with a bushing rotating ring and a bushing gear; the bushing rotating ring is a whole ring structure with two symmetrically arranged on both sides of the sealing bushing; the bushing gear and the large gear of the drive gear shaft assembly mesh and drive each other.

[0012] Preferably, the gear shaft assembly is provided with a large gear and a small gear; the small gear is provided in two symmetrically arranged on both sides of the large gear, and the gear shaft assembly is supported by angular contact ball bearings and arranged in the cavity of the stationary ring assembly.

[0013] Preferably, the intermediate ring assembly has two rings symmetrically arranged on both sides of the sealing bushing; the intermediate ring assembly includes an intermediate ring, which is a solid ring structure with a hard ring and a soft ring respectively on its two sides; the soft ring and the moving ring of the bushing form a first sealing friction pair, the hard ring and the stationary ring of the push ring assembly form a second sealing friction pair, and an intermediate ring gear is provided on the intermediate ring and meshes with the pinion of the gear shaft assembly for transmission.

[0014] Preferably, the number of teeth of the bushing gear of the rotating ring assembly is Z1, the number of teeth of the large gear of the gear shaft assembly is Z2, the number of teeth of the small gear of the gear shaft assembly is Z3, and the number of teeth of the intermediate ring gear of the intermediate ring assembly is Z4; wherein, Z2, Z4, Z1 and Z3 satisfy: Z2×Z4=2×Z1×Z3.

[0015] Preferably, the organic working gas enters the working gas mixing chamber through the working gas side throttling bushing and mixes with the nitrogen leaking from the first sealing surface and the nitrogen leaking from the second sealing surface, and is discharged from the mixed gas outlet.

[0016] Preferably, the working fluid recovery system includes a cooler, a working fluid recovery tank, a hydrocyclone separator, a filter screen, a level transmitter, and a level regulating valve; the mixed gas inlet of the working fluid recovery system is connected to the mixed gas outlet of the mechanical seal; the mixture of organic working fluid and nitrogen first passes through the cooler to condense the organic working fluid into a liquid state, and then the gas-liquid mixture enters the working fluid recovery tank, where nitrogen accumulates at the top and is separated from the nitrogen containing liquid organic working fluid by the hydrocyclone separator and the filter screen, and then returned to the working fluid recovery tank; the working fluid recovery tank is equipped with a level transmitter, and the PLC system controls the level regulating valve to maintain the liquid level in the working fluid recovery tank, and the liquid organic working fluid is recovered to the condenser hot well via the level regulating valve.

[0017] Compared with the prior art, the beneficial effects of the present invention are:

[0018] 1. This invention is applicable to 12-inch to 20-inch high-speed mechanical seals for high-power organic working fluid turbines. This type of mechanical seal reduces the rotational speed of the intermediate ring assembly to half that of the main shaft through the reduction transmission of the gear shaft assembly. This effectively reduces the frictional heat of the first sealing friction pair, which consists of the rotating ring on the rotating ring assembly and the soft ring on the intermediate ring assembly, and the second sealing friction pair, which consists of the hard ring on the intermediate ring assembly and the stationary ring on the push ring assembly. This effectively prevents the sealing surface from overheating and failing, and improves the reliability and service life of large-size high-speed mechanical seals.

[0019] 2. This invention employs process nitrogen to purge the sealed friction pair, thereby removing frictional heat. The process nitrogen pressure is higher than the pressure of the organic working fluid gas, which effectively prevents leakage of the working fluid. The mixture of organic working fluid and nitrogen first passes through the cooler of the working fluid recovery system to condense the organic working fluid into a liquid state. Then, it undergoes gas-liquid separation in the working fluid recovery tank. The hydrocyclone separator and filter further separate the organic working fluid liquid contained in the nitrogen gas. Finally, the organic working fluid is recovered to the condenser hot well through the liquid level regulating valve of the working fluid recovery system, effectively achieving zero leakage and separation and recovery of the organic working fluid into the atmospheric environment. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of the organic working fluid turbine half-speed mechanical seal of the present invention;

[0021] Figure 2 yes Figure 1 A schematic diagram showing the assembly of the intermediate rotating ring assembly 1, the gear shaft assembly 2, the intermediate ring assembly 3, and the push ring assembly 4.

[0022] Figure 3 This is a schematic diagram of the fit between the split fastening ring 6a and the main shaft 9;

[0023] Figure 4 This is a schematic diagram of the thermodynamic cycle of an organic working fluid turbine;

[0024] Figure 5 This is a diagram illustrating the isolation gas purging and leakage process;

[0025] Figure 6 This is a schematic diagram showing the connection between the working fluid recovery system 8 and the mechanical seal;

[0026] The numbers in the diagram are: 1—rotating ring assembly, 1a—sealing bushing, 1b—bushing rotating ring, 1c—bushing gear;

[0027] 2—Gear shaft assembly, 2a—Large gear, 2b—Pinner gear, 2c—Angular contact ball bearing;

[0028] 3—Intermediate ring assembly, 3a—Hard ring, 3b—Soft ring, 3c—Intermediate ring gear, 3d—Deep groove ball bearing, 3e—Collar ring;

[0029] 4—Push ring assembly, 4a—Stationary ring, 4b—Push ring seat, 4c—Spring, 4d—Push ring, 4e—Sliding key;

[0030] 5—Stationary ring assembly; 5a—Front end cover; 5b—Rear end cover; 5c—Working fluid side throttling bushing; 5d—Atmospheric side throttling bushing; 5e—Clamping plate; 5f—Screw; 5g—Keyway; 5h—Mechanical seal mounting flange;

[0031] 6—Positioning and fastening ring assembly; 6a—Split fastening ring; 6b—Set screw; 6c—Fastening screw; 6d—Axial retaining ring; CLR—Split fastening ring clearance;

[0032] 7—Isolation gas chamber; 7a—First sealing friction pair; 7b—Second sealing friction pair; 7c—Working gas mixing chamber; 7d—Isolation gas leakage chamber; GBI—Isolation gas inlet; GBO—Isolation gas outlet; D1—Mixed gas outlet; D2—Leaking gas outlet; a—Leakage at the first sealing surface; b—Leakage at the second sealing surface; c—Leakage at the organic working medium; d—Nitrogen exposure.

[0033] 8—Working fluid recovery system; 8a—Working fluid recovery tank; 8b—Level transmitter; 8c—Cooler; 8d—Swirl separator; 8e—Filter screen; 8f—Level regulating valve; CWI—Cooling water inlet; CWO—Cooling water outlet; N1—Mixed gas inlet; N2—Process gas outlet;

[0034] 9—Main spindle. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0036] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0037] It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Furthermore, the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0038] like Figures 1 to 6 As shown, an organic working fluid turbine half-speed mechanical seal and working fluid recovery system includes a rotating ring assembly 1, a gear shaft assembly 2, an intermediate ring assembly 3, a push ring assembly 4, a stationary ring assembly 5, a positioning and fastening ring assembly 6, and a working fluid recovery system 8. The rotating ring assembly 1 drives the intermediate ring assembly 3 to rotate at half speed through the gear shaft assembly 2. The rotating ring 1b on the rotating ring assembly 1 and the soft ring 3b on the intermediate ring assembly 3 form a first sealing friction pair 7a, and the hard ring 3a on the intermediate ring assembly 3 and the stationary ring 4a on the push ring assembly 4 form a second sealing friction pair 7b. The relative speed of the first sealing friction pair 7a and the second sealing friction pair 7b is half the speed of the main shaft 9. Process nitrogen is introduced into the isolation chamber 7 to remove frictional heat.

[0039] The nitrogen pressure is higher than the organic working gas pressure to prevent the working gas from leaking into the atmosphere; the working gas recovery system 8 is connected to the mixed gas outlet D1 to separate and recover the mixture of organic working gas and nitrogen.

[0040] This invention reduces frictional heat by ensuring that the relative rotational speeds of the first sealing friction pair 7a and the second sealing friction pair 7b are both half the rotational speed of the main shaft 9. This effectively prevents overheating and failure of the sealing surface, thus improving the reliability and service life of large-size high-speed mechanical seals. The working fluid recovery system 8 is connected to the mixed gas outlet D1, achieving zero leakage of the organic working fluid and its separation and recovery; ultimately, it enables safe, stable, and environmentally friendly operation of the organic working fluid turbine.

[0041] In practical implementation, the stationary ring 4a of the thrust ring assembly 4 is fixed to the mechanical seal mounting flange 5h of the organic working fluid turbine using fasteners. This technical measure enables the assembly of the rotating components of the mechanical seal within the stationary ring.

[0042] The stationary ring assembly 5 is divided into two parts along the axial direction: a front cover 5a and a rear cover 5b. The front cover 5a is fitted with a working fluid-side throttling bushing 5c, and the rear cover 5b is fitted with an atmospheric-side throttling bushing 5d. After the rotating ring assembly 1, gear shaft assembly 2, intermediate ring assembly 3, and push ring assembly 4 are assembled in the chamber of the stationary ring assembly 5, the axial positioning and fixing of the moving and stationary components of the mechanical seal are achieved by means of a retaining plate 5e. Using this technology, the mechanical seal does not need to be disassembled during installation, making it a cartridge-type mechanical seal.

[0043] like Figure 2 As shown, the sealing bushing 1a of the rotating ring assembly 1 is fixed to the main shaft 9 by the positioning and fastening ring assembly 6 and rotates together with it.

[0044] Among them, the sealing bushing 1a is a complete ring structure, and there is a sealing ring between the sealing bushing 1a and the main shaft 9 to prevent the working fluid from leaking along the inner diameter of the sealing bushing 1a.

[0045] The positioning and fastening ring assembly 6 consists of a split fastening ring 6a, a set screw 6b, a fastening screw 6c, and an axial retaining ring 6d; the axial retaining ring 6d is used to achieve axial positioning of the mechanical seal in the main shaft 9.

[0046] like Figure 3 As shown, the split retaining ring 6a has a two-half structure with a gap between the two halves. The gap value CLR is determined according to the torque of the sealing friction surface. After the split retaining ring 6a is tightened by the retaining screw 6c, it should grip the main shaft 9 without any gap.

[0047] The sealing bushing 1a is provided with a bushing rotating ring 1b and a bushing gear 1c. The bushing rotating ring 1b is a single ring structure with two symmetrically arranged rings on both sides of the sealing bushing 1a. This technical measure can prevent leakage. A sealing ring is provided between the bushing rotating ring 1b and the sealing bushing 1a; the bushing gear 1c meshes with the large gear 2a of the gear shaft assembly 2. This technical measure is used to achieve the transmission function.

[0048] In specific implementation, such as Figure 2 As shown, the gear shaft assembly 2 is provided with a large gear 2a and a small gear 2b; two small gears 2b are provided and symmetrically arranged on both sides of the large gear 2a. The gear shaft assembly 2 is supported by an angular contact ball bearing 2c and arranged in the cavity of the stationary ring assembly 5.

[0049] In specific implementation, two intermediate ring assemblies 3 are set and symmetrically arranged on both sides of the sealing bushing 1a. The intermediate ring assembly 3 includes an intermediate ring, which is a whole ring structure with a hard ring 3a and a soft ring 3b on its two sides respectively. A sealing ring is set between the hard ring 3a, the soft ring 3b and the intermediate ring.

[0050] A deep groove ball bearing 3d and a retaining ring 3e are provided between the intermediate ring and the sealing bushing 1a to support the intermediate ring on the sealing bushing 1a.

[0051] An intermediate ring gear 3c is provided on the intermediate ring. The intermediate ring gear 3c meshes with the pinion 2b of the gear shaft assembly 2 to achieve transmission.

[0052] The push ring assembly 4 consists of a stationary ring 4a, a push ring seat 4b, a spring 4c, a push ring 4d, and a sliding key 4e. The sliding key 4e of the push ring assembly 4 engages with the keyway 5g of the stationary ring assembly 5 to achieve anti-rotation and axial sliding guidance functions. The stationary ring 4a on the push ring assembly 4 contacts the hard ring 3a of the intermediate ring assembly 3 and is pressed by the spring 4c installed in the push ring seat 4b.

[0053] Selectively, but preferably, the rotating ring 1b of the rotating ring assembly 1 is made of silicon carbide hard material; the soft ring 3b of the intermediate ring assembly 3 is made of graphite wear-resistant material, and the two constitute the first sealing friction pair 7a;

[0054] The hard ring 3a of the intermediate ring assembly 3 is made of silicon carbide hard material, and the stationary ring 4a of the push ring assembly 4 is made of graphite wear-resistant material. The two together constitute the second sealing friction pair 7b.

[0055] The first and second sealing friction pairs are pressed together by the push ring assembly 4. Technically, during relative rotation, the micron-level gap between the friction pairs effectively prevents leakage.

[0056] In specific implementation, the number of teeth of the bushing gear 1c of the rotating ring assembly 1 is Z1, the number of teeth of the large gear 2a of the gear shaft assembly 2 is Z2, the number of teeth of the small gear 2b of the gear shaft assembly 2 is Z3, and the number of teeth of the intermediate ring gear 3c of the intermediate ring assembly 3 is Z4; wherein Z2, Z4, Z1, and Z3 satisfy: Z2×Z4=2×Z1×Z3. This tooth number setting enables the rotational speed of the intermediate ring assembly 3 to be half the rotational speed of the main shaft 9, thereby achieving a relative rotational speed of half the rotational speed of the main shaft 9 for both the first sealing friction pair 7a and the second sealing friction pair 7b. By reducing the relative rotational speed, frictional heat can be effectively reduced, thus effectively avoiding overheating and failure of the sealing surface, and improving the reliability and service life of the large-size high-speed mechanical seal.

[0057] Figure 4 This is a schematic diagram of the thermodynamic cycle of an organic working fluid turbine. Specifically, the high-temperature, high-pressure gaseous organic working fluid (organic working fluid gas) enters the organic working fluid turbine, expands, and performs work, resulting in a decrease in pressure and temperature. The organic working fluid then enters the condenser through the exhaust port and condenses into a liquid state, accumulating in the hot well at the bottom of the condenser. After being pressurized by the working fluid pump, it enters the preheater for heating, and finally evaporates into a gaseous state in the evaporator, re-entering the organic working fluid turbine through the inlet, thus realizing the cycle of the organic working fluid.

[0058] Mechanical seals are installed on both sides of the balance chamber of the organic working fluid turbine to prevent the organic working fluid from leaking into the atmosphere.

[0059] The gaseous organic working medium leaking from the mechanical seal is mixed with the leaking nitrogen and then fed into the gas-liquid separator. Since the pressure of the condenser hot well in the system is the lowest, the mixed gas can be directed to the gas-liquid separator and the liquid organic working medium can be recovered under the action of pressure difference. The nitrogen separated by the gas-liquid separator is mixed with the nitrogen in the mechanical seal isolation gas leakage chamber for 7 days and then sent to the gas treatment station for pressurization and recycling.

[0060] Figure 5Diagram of isolation gas purging and leakage. Process nitrogen enters the isolation gas chamber 7 through the isolation gas inlet GBI to purge the first sealing friction pair 7a and the second sealing friction pair 7b, carrying away frictional heat before being discharged from the isolator outlet GBO. The process nitrogen pressure is higher than the pressure of the organic working fluid gas, thus effectively preventing the organic working fluid from leaking into the atmosphere. This pressure of process nitrogen is called isolation gas. Otherwise, the higher pressure of the organic working fluid gas would cause leakage of the organic working fluid into the atmosphere.

[0061] like Figure 5 As shown, the organic working gas (gaseous organic working gas) enters the working gas mixing chamber 7c through the working gas-side throttling bushing 5c ​​and mixes with the nitrogen leaking from the first sealing surface a and the nitrogen leaking from the second sealing surface b, and is discharged from the mixed gas outlet D1. The nitrogen leaking from the first sealing surface a and the nitrogen leaking from the second sealing surface b enter the isolation gas leakage chamber 7d and are discharged from the leakage gas outlet D2. A trace amount of nitrogen d leaks into the atmospheric environment through the atmospheric side throttling bushing 5d.

[0062] like Figure 6 As shown, the working fluid recovery system 8 includes a cooler 8c, a working fluid recovery tank 8a, a hydrocyclone separator 8d, a filter screen 8e, a level transmitter 8b, and a level regulating valve 8f.

[0063] like Figure 6 As shown, the mixed gas inlet N1 of the working fluid recovery system 8 is connected to the mixed gas outlet D1 of the mechanical seal. The mixture of organic working fluid and nitrogen first passes through the cooler 8c of the working fluid recovery system. The organic working fluid transfers heat to the cooling water passing through the cooler 8c and condenses into a liquid state. Then, the gas-liquid mixture enters the working fluid recovery tank 8a. The liquid organic working fluid accumulates at the bottom of the working fluid recovery tank 8a, and the nitrogen gas accumulates at the top of the working fluid recovery tank 8a. The liquid organic working fluid contained in the nitrogen gas is separated by the hydrocyclone separator 8d and the filter screen 8e and sent back to the working fluid recovery tank 8a. The working fluid recovery tank 8a is equipped with a level transmitter 8b. The PLC system controls the level regulating valve 8f to maintain the level of the working fluid recovery tank 8a. The liquid organic working fluid is recovered to the condenser hot well through the level regulating valve 8f, thereby effectively realizing the separation and recovery of the organic working fluid.

[0064] The technical solutions provided by the embodiments of the present invention have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of the embodiments of the present invention. The descriptions of the embodiments above are only for helping to understand the principles of the embodiments of the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the embodiments of the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. An organic working fluid turbomachinery half speed mechanical seal and working fluid recovery system, characterized by: The rotating ring assembly (1), gear shaft assembly (2), intermediate ring assembly (3), push ring assembly (4), static ring assembly (5), positioning fastening ring assembly (6), working medium recovery system (8); The rotating ring assembly (1) drives the intermediate ring assembly (3) to rotate at half speed through the gear shaft assembly (2); The shaft sleeve dynamic ring (1b) on the rotating ring assembly (1) and the soft ring (3b) on the intermediate ring assembly (3) form a first sealing friction pair (7a), The sealing shaft sleeve (1a) of the rotating ring assembly (1) is fixed on the main shaft (9) and rotates with it through the positioning fastening ring assembly (6); The sealing shaft sleeve (1a) is provided with a shaft sleeve dynamic ring (1b) and a shaft sleeve gear (1c); The shaft sleeve dynamic ring (1b) is an integral ring structure and is provided with two symmetrical arrangements on both sides of the sealing shaft sleeve (1a); The shaft sleeve gear (1c) and the large gear (2a) of the driving gear shaft assembly (2) are meshed and transmitted; The hard ring (3a) on the intermediate ring assembly (3) and the static ring (4a) on the push ring assembly (4) form a second sealing friction pair (7b); The intermediate ring assembly (3) is provided with two symmetrical arrangements on both sides of the sealing shaft sleeve (1a); the intermediate ring assembly (3) comprises an intermediate ring, the intermediate ring is an integral ring structure and is provided with a hard ring (3a) and a soft ring (3b) on both sides thereof; the soft ring (3b) and the shaft sleeve dynamic ring (1b) form a first sealing friction pair (7a), the hard ring (3a) and the static ring (4a) of the push ring assembly (4) form a second sealing friction pair (7b), and the intermediate ring is provided with an intermediate ring gear (3c) and is meshed and transmitted with the pinion gear (2b) of the gear shaft assembly (2); The relative rotating speed of the first sealing friction pair (7a) and the second sealing friction pair (7b) is half of the rotating speed of the main shaft (9); Process nitrogen is introduced into the isolation gas chamber (7) to carry away the friction heat; the nitrogen pressure is higher than the pressure of the organic working medium gas to prevent the working medium from leaking into the atmospheric environment; The working medium recovery system (8) is communicated with the mixed gas outlet (D1) to separate and recover the mixed gas of the organic working medium and nitrogen.

2. The organic working fluid turbomachinery half speed mechanical seal and working fluid recovery system of claim 1, wherein: The gear shaft assembly (2) is provided with a large gear (2a) and a small gear (2b); The small gear (2b) is provided with two symmetrical arrangements on both sides of the large gear (2a), and the gear shaft assembly (2) is supported by an angular contact ball bearing (2c) and arranged in the cavity of the static ring assembly (5).

3. The organic working fluid turbomachinery half speed mechanical seal and working fluid recovery system of claim 1, wherein: The number of teeth of the shaft sleeve gear (1c) of the rotating ring assembly (1) is Z1, the number of teeth of the large gear (2a) of the gear shaft assembly (2) is Z2, the number of teeth of the small gear (2b) of the gear shaft assembly (2) is Z3, and the number of teeth of the intermediate ring gear (3c) of the intermediate ring assembly (3) is Z4; Wherein, Z2, Z4, Z1 and Z3 satisfy: Z2×Z4=2×Z1×Z3.

4. The organic working fluid turbomachinery half speed mechanical seal and working fluid recovery system of claim 1, wherein: The organic working medium gas enters the working medium gas mixing chamber (7c) through the working medium side throttling bushing (5c), mixes with the leaked nitrogen of the first sealing surface and the leaked nitrogen of the second sealing surface, and is discharged from the mixed gas outlet (D1).

5. The organic working fluid turboset half speed mechanical seal and working fluid recovery system of claim 1, wherein: The working medium recovery system (8) comprises a cooler (8c), a working medium recovery tank (8a), a hydrocyclone (8d), a filter screen (8e), a liquid level transmitter (8b) and a liquid level regulating valve (8f); The mixed gas inlet (N1) of the working medium recovery system (8) is communicated with the mixed gas outlet (D1) of the mechanical seal; the mixed gas of the organic working medium and nitrogen firstly passes through the cooler (8c) to condense the organic working medium into liquid state, then the gas-liquid mixture enters the working medium recovery tank (8a), the nitrogen is gathered at the top of the working medium recovery tank (8a) and the organic working medium liquid contained in the nitrogen is separated by the hydrocyclone (8d) and the filter screen (8e) and is sent back to the working medium recovery tank (8a); the working medium recovery tank (8a) is provided with the liquid level transmitter (8b), the PLC system controls the liquid level regulating valve (8f) to maintain the liquid level of the working medium recovery tank (8a), and the liquid organic working medium is recovered to the condenser hot well through the liquid level regulating valve (8f).

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